Earlier quoted context omitted.
Missing context implies that their failure to provide it was an oversight. There was not even an attempt at providing context here, because doing so would be unpopular.
With cops wearing body cams, that evidence should be abundant. Its absence is telling. Collecting evidence is pretty much job #1 for the police. Without that, they can't establish guilt of the accused. When dozens of cops were involved in a beatdown and not a single one can produce a shred of evidence, we assume that the protesters were innocent.
Excellent point. If denial / lack of evidence is the SoP for any Police Department, what are they even doing? Defense Lawyers would barely have to work for their pay.